This study is undertaken to investigate the effect of drugs of abuse, morphine and nicotine on diabetes mellitus. Diabetes mellitus is the most common endocrine disease and consumes about 15% of annual health care expenditure in the United States. At the same time 36% of the population smokes cigarette and the opiates also rank high among the commonly abused agents. The long term goal of this study is to examine the hypothesis 1) Acutely or chronically administered nicotine or morphine accelerates the onset of diabetes. 2) Complications of diabetes worsen under the influence of chronically ingested nicotine/morphine. 3) the degenerative processes of diabetes will alter the receptor binding characteristics of morphine and nicotine receptor (ie. opioid receptors, nicotinic receptors and muscarinic receptors). We will examine these hypotheses with the following specific aims in mind: A) To evaluate the effect of morphine and nicotine on the onset of diabetes, rats will be treated with nicotine and morphine acutely or chronically and thereafter challenged with varying doses of streptozotocin (20, 40, 60 mg/kg)) intraperitoneally to induce diabetes. B) To examine the impact of morphine and nicotine on diabetic state, rats will first of all be made diabetic with intraperitonial injection of 60 mg/kg of streptozotocin (STZ). These diabetic rats will then be subjected to chronic administration of nicotine (8 weeks). Some groups of these rats will also be treated with insulin. The control will receive the vehicle. During the eight weeks, parameters to be monitored include: possible occurrence of diarrhea/constipation, body weight, fluid consumption, blood glucose level from an incision on the tail. At the end of the treatment period, animals will be killed by decapitation and parameters such as blood insulin and glucose level, by specific diagnostic kits will be measured, histopathology of the pancreas will also be examined. C) Radio ligand binding studies will be carried out to determine the receptor density of opioid receptors, nicotinic receptors, and muscarinic receptors in the treated and untreated rats. Examining the impact of attention since a significant number of US population and the world population suffer from addiction and may also have diabetes at the same time. The proposed study may increase the understanding of basic mechanisms of drug abuse in diabetes and may provide important practical information for developing new strategies for treatment.